Over the past year, thousands of vehicles changed hands at collector car auctions in North America. Plenty of the familiar American muscle, European sports and classic luxury cars have crossed the block, but certain models are being auctioned much more frequently than even just a couple of years ago.

The most glaring trend revealed on the graph is that far more Porsche 911s have to come to market than previously, but that should not be a surprise. The 911 market famously went ballistic over the course of 2015 and peaked earlier this year. Seeing ever-higher prices at auction and realizing that the trend was not sustainable, everyone with an air-cooled Porsche in the garage decided they could make money selling their car, and the auction companies were more than happy to consign.

As for the newer Dodge Challengers, that can largely be attributed to the relatively high number of new Challenger Hellcats, which are still relatively difficult to buy at a dealership, that have come up at Mecum and Barrett-Jackson. While Ford and Chevrolet don’t exactly have comparable versions of their own muscle cars, late-model Camaros and Mustangs have also come up with increasing regularity, specifically as Mecum continues consigning an increasing number of more modern cars. Including the 911s, six out of the 10 cars on the graph are from after 1980, and nine are from after 1970. There has been much talk of newer and newer cars entering the collector car market, and this is confirmed by examining recent auction offerings.